1. Field of the Invention
The present invention relates to a quantity-of-light adjusting device for use in a video camera, a digital still camera or the like.
2. Description of Related Art
For motion-image taking cameras such as video cameras, there is used a motion-image quantity-of-light adjusting device which continuously varies a diaphragm aperture from a full-aperture state up to a full-closed state. On the other hand, for still-image taking cameras such as digital still cameras, there is used a still-image quantity-of-light adjusting device which switches a diaphragm aperture between two positions, i.e., a full-aperture state and a small-aperture state (e.g., F8), or which is capable of performing a shutter action in addition to the quantity-of-light adjusting function.
Further, a quantity-of-light adjusting device which is capable of adjusting a diaphragm aperture to at least three positions by means of a turret diaphragm mechanism is disclosed in, for example, Japanese Laid-Open Utility Model Application No. HEI 3-52725. In this quantity-of-light adjusting device, a mechanical diaphragm mechanism is used to mechanically restrict a diaphragm member to the full-aperture position by means of a torsion spring and this position is changed over to another position by transmitting a driving force of a driving part to the diaphragm member through gears.
In accordance with one aspect of the invention, there is provided a quantity-of-light adjusting device, which comprises a drive source, a base member having an opening formed therein, and a blade arranged to move by being driven by the drive source and having three openings formed therein side by side in a row in a moving direction of the blade, wherein, among the three openings formed in the blade, the opening situated in the middle of the row is larger than the opening formed in the base member.
In accordance with another aspect of the invention, there is provided a quantity-of-light adjusting device, which comprises a drive source, a base member having an opening formed therein, and a blade arranged to move by being driven by the drive source and having two openings formed therein side by side in a row in a moving direction of the blade, wherein, between the two openings formed in the blade, there is provided a light blocking area which is larger than the opening formed in the base member.
These and other aspects and features of the invention will become apparent from the following detailed description of preferred embodiments thereof taken in connection with the accompanying drawings.